In the past, as this type of solar radiation shielding apparatus, a solar radiation member lifting and lowering apparatus that supports first and second solar radiation shielding members suspended from a head box and can lift and lower the first and second solar radiation shielding members independently by effecting the operation of first and second lifting and lowering operation sections with operation of one endless operating cord hung from the head box has been disclosed (see, for example, Patent Document 1). The solar radiation member lifting and lowering apparatus includes first and second stopper units that allow a state in which the solar radiation shielding members are not lowered as a result of the first and second solar radiation shielding members being prevented from being lowered under the own weights thereof or a state in which the solar radiation shielding members are lowered as a result of the first and second solar radiation shielding members being allowed to be lowered under the own weights thereof to be selected, a first clutch unit that allows a lifting operation of the first solar radiation shielding member and a lowering operation thereof due to the own weight thereof by making the first lifting and lowering operation section and the first stopper unit operate with operation of the operating cord to one side without lifting or lowering the second solar radiation shielding member or an operation to prevent the falling of the first solar radiation shielding member due to the own weight thereof to stop the falling of the first solar radiation shielding member due to the own weight thereof to be selected, and a second clutch unit that allows a lifting operation of the second solar radiation shielding member and a lowering operation thereof due to the own weight thereof by making the second lifting and lowering operation section and the second stopper unit operate with operation of the operating cord to the other side without lifting or lowering the first solar radiation shielding member and an operation to prevent the falling of the second solar radiation shielding member due to the own weight thereof to stop the falling of the second solar radiation shielding member due to the own weight thereof to be selected.
The first clutch unit is formed of a first rotating drum that is rotated based on the operation of the operating cord, a first transfer drum driving the first lifting and lowering operation section, and a first clutch section transferring the rotation of the first rotating drum to the first transfer drum. The first clutch section is configured such that the turning force of the first rotating drum based on the operation of the operating cord to one side can be transferred to the first transfer drum and the first transfer drum is freely rotatable independently of the first rotating drum when the first transfer drum is rotated based on the falling of the first solar radiation shielding member due to the own weight thereof. Moreover, the second clutch unit is formed of a second rotating drum that is rotated based on the operation of the operating cord, a second transfer drum driving the second lifting and lowering operation section, and a second clutch section transferring the rotation of the second rotating drum to the second transfer drum. The second clutch section is configured such that the turning force of the second rotating drum based on the operation of the operating cord to the other side can be transferred to the second transfer drum and the second transfer drum is freely rotatable independently of the second rotating drum when the second transfer drum is rotated based on the falling of the second solar radiation shielding member due to the own weight thereof.
Furthermore, the first and second clutch sections are each formed of a clutch drum rotatably supported on a shaft, a guide groove formed on the outer periphery of the clutch drum, a clutch ball that moves along the guide groove, and a stop spring that prevents the rotation of the clutch drum based on the turning force exerted from the clutch drum and integrally rotates the first or second rotating drum and the clutch drum based on the turning force exerted from the first or second rotating drum. The above-described guide groove is formed of an engagement groove that makes it possible to transfer the turning force of the first or second rotating drum to the first or second transfer drum via the clutch ball and a release groove leading out of the engagement groove in such a way as to be offset to the side where the first or second rotating drum is located, the release groove allowing the first or second transfer drum to rotate freely with respect to the first or second rotating drum. Moreover, when the turning force of the first rotating drum is transferred to the first transfer drum via the clutch ball, the turning force of the second rotating drum is not transferred to the second transfer drum; when the turning force of the second rotating drum is transferred to the second transfer drum via the clutch ball, the turning force of the first rotating drum is not transferred to the first transfer drum. In the solar radiation member lifting and lowering apparatus structured as described above, by making it possible to lift and lower the two solar radiation shielding members independently with one operating cord and automatically perform lifting or lowering operation of each solar radiation shielding member with one-touch operation of the operating cord, the solar radiation shielding members can be lifted and lowered easily.
Patent Document 1: Japanese Patent No. 4119692 (claim 1, paragraphs [0043] and [0157])